Here is the question: "Polymorphism is being used whenever an object has a “declared type” that is either a superclass of the object’s actual type, or an ____ implemented by the actual type?"
I think the answer is subclass, but I'm not positive.
Based on the context of this sentence with the word "an" before the blank and "implemented", I think the answer here should be interface
I think it might be either interface or abstract class since the questions uses "an" and both are used for polymorphism.
No, the "abstract class" case would be covered by the "superclass" situation mentioned earlier in the sentence.